The purpose of this project is to determine the mental health and behavioral effects of the epidemic of Acquired Immune Deficiency Syndrome (AIDS) on a group of homosexual males (N=700) who do not have AIDS but who are at risk of contracting the disease. The sample will be drawn from diverse channels within the New York community. Data will be collected at two time points, one year apart, through face-to-face interview. The method proposed includes both retrospective and prospective components. The effects of the AIDS epidemic will be assessed using three sets of outcome measures: specific and non-specific psychological distress, drug use, and sexual behavior. Features of the epidemic expected to have an impact on the three areas of functioning are: death and illness in the social network due to AIDS, and subjective threat of contracting AIDS. Social network support and selected personal dispositions are assessed in order to estimate their direct effects on functioning as well as their mediation of the relationship between AIDS-related stressors and functioning. The research utilizes the framework of life stress and illness within which to study these effects, and includes both pathological/undesirable outcomes as well as adaptive outcomes within its scope. Many of the instruments to be used in this study have been adapted from other psychiatric epidemiologic field studies. Other instruments, notably those measuring sexual behavior and drug use, have been newly developed here, thereby addressing a serious methodological problem confronted by many AIDS researchers. Causal modeling will provide information on: (1) the duration of reactions to AIDS-related stressors, (2) the extent to which individuals habituate to newly arising AIDS-related stressors, and (3) the processes by which AIDS-related stressors are coped with. This research contributes to understanding the stress-adaptation process, and it also has implications for understanding the etiology of AIDS.